The invention relates to a method and apparatus for containing and agitating at least one article. The invention has application in any situation where articles are required to be treated by agitation for purposes as varied as cleaning, polishing, grinding, granulating, peeling and coating. Preferably, the invention is used in the laundry field in order to carry out cleaning (washing) or fabric treatment processes. Particularly, but not exclusively, the invention relates to an improved washing machine.
Devices which agitate articles within a rotating drum in the presence of a fluid are known. For example, U.S. Pat. No. 5,350,323, discloses a dual drum mixer which can be used to mix, homogenize or react at least two components. The device is a container made of two separately driveable pipe lengths adjacent to one another. The container is sealed, with fluid being injected into the container through its longitudinal axes. The device is limited in use in that fluid entry is only through its axes and the fluid must be sealed within the container in order for proper mixing or agitation to occur.
In agitation devices such as conventional washing machines, a perforated drum is used to contain articles as they are agitated in the presence of water and detergent in order to remove dirt. The dirt is displaced into the water, and the water is removed from the drum by passing through the perforations. In front-loading washing machines, agitation is caused by the rotation of the drum about a generally horizontal axis so that the articles tumble over one another and rub against each other and against the walls of the drum. However, the rotational speed of the drum is limited because, if the speed is too high, the articles will merely be pressed under centrifugal forces against the interior walls of the drum. The articles then rotate with the drum and no agitation with respect to the drum or with respect to other articles is achieved. The amount of agitation which can be applied to the articles by front-loading washing machines is therefore limited. This means that, in order to achieve a specific standard of cleanliness, the machine must operate for a minimum period of time.
In order to overcome many problems inherent in the prior art, the present invention provides an apparatus and method for enhancing the agitation of articles. The apparatus comprises a drum for containing and agitating an article, wherein the drum comprises at least two rotatable drum portions in rotatable connection with one another, a rotator member in connection with each rotatable drum portion for rotating the drum portion about an axis. Preferably the drum has at least one port for intake or exhaust of a liquid into or out of an area internal to the drum. More preferably, the at least one port is located on a peripheral portion of at least one of the rotatable drum portions. The drum can be seated within a tank.
The apparatus can include a drive in connection with each rotator member. The rotatable drum portions are, preferably, rotatable about a common axis, and the axis can be horizontal or inclined to the vertical. The rotatable drum portions can be of a variety of shapes and sizes so that the apparatus can function as a polisher, grinder, granulator, peeler, coater or washing machine. The apparatus is preferably a washing machine.
The drive comprises a motor connected to a coupler, and a controller can be connected to the motor to control speed and directional rotation of the rotatable drum portions. The rotator member can be connected to a periphery of each rotatable drum portion, or it can be connected to a shaft adjoining each rotatable drum portion. The rotator member acts as a friction providing element to facilitate rotation of the rotatable drum portions.
The drive and rotator member couple such that the rotatable drum portions can rotate independently of one another. The rotatable drum portions can be rotated at different speeds and different directions in order to enhance agitation.
The invention also encompasses a method of providing enhanced agitation. The method comprises inserting at least one solid article into a drum, wherein the drum comprises a first rotatable drum portion and a second rotatable drum portion in rotatable connection with one another; and rotating the first and second drum portions independently of one another to agitate the article. Preferably, a fluid is provided within the drum as the first and second drum portions are rotated. The fluid is preferably added to or exhausted from the drum through at least one port at a peripheral portion of the drum.
The rotatable drum portions can be rotated at a variety of speeds and directions. For example, the rotatable drum portions can be rotated in opposite directions; at the same speed in opposite directions; at different speeds in the same direction; at different speeds in opposite directions; at the same speed and in the same direction; or at least one of the rotatable drum portions can be held stationary while the other rotatable drum portion is rotated.
In another embodiment, the invention provides an apparatus which comprises a drum for containing and agitating an article, wherein the drum comprises at least two rotatable drum portions in rotatable connection with one another, and a rotator member in connection with each rotatable drum portion for rotating the drum portion about an axis. Two of the rotatable drum portions at opposite ends of the drum have end walls attached thereto. An opening for inserting the article into the drum can be provided at an end wall or at a peripheral portion of one or more rotatable drum portions. A door can be provided to maintain the article within the drum during operation. Preferably, one of the rotatable drum portions is located inside another rotatable drum portion, and the rotatable drum portions can be mounted on concentric shafts.